{smcl}
{* 17apr2007}{...}
{cmd:help mata mm_which()}
{hline}

{title:Title}

{p 4 4 2}
{bf:mm_which() -- Positions of nonzero elements}


{title:Syntax}

{p 8 12 2}
{it:real vector}
{cmd:mm_which(}{it:real vector v}{cmd:)}


{title:Description}

{p 4 4 2} {cmd:mm_which()} returns the position of the nonzero elements
in {it:v}.


{title:Remarks}

{p 4 4 2}Example:

        {com}: x = uniform(10,1)
        {res}
        {com}: x
        {res}        {txt}          1
             {c TLC}{hline 15}{c TRC}
           1 {c |}  {res}.6942035381{txt}  {c |}
           2 {c |}  {res}.9866539028{txt}  {c |}
           3 {c |}  {res} .339872522{txt}  {c |}
           4 {c |}  {res}.4785448909{txt}  {c |}
           5 {c |}  {res}.1890356159{txt}  {c |}
           6 {c |}  {res}.2186723398{txt}  {c |}
           7 {c |}  {res} .495693512{txt}  {c |}
           8 {c |}  {res}.7756144393{txt}  {c |}
           9 {c |}  {res} .733696372{txt}  {c |}
          10 {c |}  {res}.4224797708{txt}  {c |}
             {c BLC}{hline 15}{c BRC}

        {com}: mm_which(x:>.5)
        {res}       {txt}1
            {c TLC}{hline 5}{c TRC}
          1 {c |}  {res}1{txt}  {c |}
          2 {c |}  {res}2{txt}  {c |}
          3 {c |}  {res}8{txt}  {c |}
          4 {c |}  {res}9{txt}  {c |}
            {c BLC}{hline 5}{c BRC}{txt}


{title:Conformability}

    {cmd:mm_which(}{it:v}{cmd:)}
           {it:v}: 1 {it:x c} or {it:r x} 1
      {it:result}: 1 {it:x c1} or {it:r1 x} 1.


{title:Diagnostics}

{p 4 4 2}{cmd:mm_which(0)} returns {cmd:J(0,0,.)}.


{title:Source code}

{p 4 4 2}
{help moremata_source##mm_which:mm_which.mata}


{title:Author}

{p 4 4 2} Ben Jann, University of Bern, jann@soz.unibe.ch


{title:Also see}

{p 4 13 2}
Online:  help for {bf:{help mf_select:[M-5] select()}},
{bf:{help moremata}}
